Please help translating this.

Tintin and Haddock are in a car and it's raining. Haddock is irritated by the rain.
I tried to translate the text on the image. But I don't understand the parts of the windscreen wipers.
If I understand correctly they fail to work properly due to humidity. Can somebody help me translate the texts? Thank you!

This is already very cool! Thank you! I also wanted to know why the windscreen wipers stopped working and why they suddenly can't be stopped. Why would windscreen wipers stop working due to humidity? This story was written in 1960. Was this a common problem in that time? It's not a very important part of the story but I really would like to understand this side joke.
(Later on they even go to a garage to repair them, I think)